In support disk bearings of the type described above, there is the general problem that the peripheral bearing rings of the support disks are relatively strongly heated during operation, in particular because of the flexing work occurring between the rotor shaft and the bearing surface.
This problem occurs both with axial thrust-free support disk bearings and with support disk bearings having pairs of support disk arranged in a crossed manner in particular. With bearings having support disk bearings arranged in a crossed manner, flexing work is additionally generated by the rotor shaft because of an axial thrust component on the bearing ring. The frictional heat generated by this thrust component also stresses the bearing ring.
Thus, over time the material of the bearing ring becomes fatigued, with the result that damage occurs in the area of the peripheral bearing surface of the bearing ring. In addition, there is the danger that the bearing ring may become separated from the hub body, in particular in the edge area.
Many differing support disk bearings for open-end spinning rotors have been developed in the past, particularly differing in the shape of the bearing rings and in the manner in which the bearing rings are fixed in place on the hub body.
For example, German Patent Publication DE 34 47 600 A1 describes a support disk whose hub body has a groove on its exterior circumference into which the bearing ring, which is made of a plastic material, is cast and thereby axially fixed. In addition, the bearing ring has a so-called cooling groove on its outer circumference, i.e. in the area of its bearing surface, which is offset in respect to this groove.
A similar type of embodiment is known from German Patent Publication DE 36 15 777 A1. In this case the hub body has a radially projecting rib in its center area instead of a groove. The bearing ring of this known support disk is intentionally formed without a groove.
Other support disks which are part of the prior art have hub bodies with one or several grooves and/or one or several radially projecting ribs. Generally, the bearing ring of these support disks has a cooling groove (e.g., German Patent Publication DE 37 19 445 A1).
Although in connection with the above mentioned known support disks a partial dissipation of the heat generated by the flexing work could be achieved, the danger continues to remain that the bearing ring is separated from the hub body over time, in particular in the area of the outer edges of the bearing ring.
It has therefore already been proposed to clamp the flanks of the bearing ring in the hub body. For example, German Patent Publication DE 195 49 466 A1 describes a support disk with a hub body which has a bell-shaped profile on its exterior circumference as well as an annular groove, closed on itself, in the area of the lateral faces of the hub body. The bearing ring made of a polymeric material is cast into these structures, so that an almost interlocking fixation of the bearing ring on the hub body results.
Although an improvement of the fastening of the bearing ring on the hub body was achieved by this embodiment in accordance with German Patent Publication DE 195 49 466 A1, the known support disks are not yet optimal, in particular in respect to heat dissipation.